1. Technical Field
The invention relates to a communication system including a plurality of interconnected controlling devices and a controlled device, functionality of the controlled device being associated with an abstract representation, referred to as AR, which provides an interface for controlling the controlled device, the AR for the controlled device being installed on a first controlling device from said plurality.
The invention further relates to a controlling device for use in a communication system including a plurality of interconnected controlling devices and a controlled device, functionality of the controlled device being associated with an abstract representation, referred to as AR, which provides an interface for controlling the controlled device, the AR for the controlled device being installed on another controlling device from said plurality.
The invention further relates to a controlled device for use in a communication system including a plurality of interconnected controlling devices and said controlled device, functionality of the controlled device being associated with an abstract representation, referred to as AR, which provides an interface for controlling the controlled device, the AR for the controlled device being installed on another controlling device from said plurality.
2. Description
A typical home audiovisual system includes a number of devices, e.g. a radio receiver, a tuner/decoder, a CD player, a pair of speakers, a television, a VCR, a tape deck, and so on. These devices are usually interconnected to allow one device, e.g. the television, to control another, e.g. the VCR. One device, such as e.g. the tuner/decoder, is usually the central device, providing central control over the others. Control buttons and switches are usually located on the front of the tuner as well as on a handheld remote control unit. A user can control all devices by means of the central device or the remote control unit.
As these devices have become more versatile and more complex, simple manual control is no longer sufficient. Furthermore, as more and more devices become available, interoperability starts to become a problem. Many vendors use their own communication protocols to allow their devices to interact, but devices from different vendors cannot interact. To overcome these problems, several interoperability standards have been defined, which allow different devices to exchange messages and information and to control each other. One well-known standard is the Home Audio/Video Interoperability (HAVi) standard, version 1.0 of which was published in January 2000, and which is available on the Internet at the address http://www.havi.org/. Another well-known standard is the domestic digital bus (D2B) standard, a communications protocol described in IEC 1030.
In a system according to such a standard, devices are interconnected in a network using a standard bus, e.g. an IEEE 1394 serial communication bus, and exchange information, such as messages, data and commands, over this network according to the standard. Standards such as HAVi define the protocol for such exchanges, allowing devices from different vendors to interact. Users can add new devices to the network, and they immediately become available to other devices. The protocol for xe2x80x9cdiscoveringxe2x80x9d such a new device is also standardized.
A device can act as a controlling device, thereby controlling another device, called the controlled device. For example, a tuner/decoder may control an amplifier or speakers. This type of control is typically done in a vendor-specific fashion, as it requires access to the internal hardware of the controlled devices. To allow arbitrary devices to interact with another device, standards such as HAVi or D2B define the concept of an abstract representation (AR), which provides an interface to the functionality of a controlled device. Application devices wishing to interact with a controlled device can now interact with the AR, installed on a controlling device, rather than directly with the controlled device itself. The controlling device then translates the information received from said application device into instructions, possibly in a proprietary fashion, which are sent to the controlled device. Any feedback from the controlled device is translated back and sent to the application device.
There may be more than one controlling device in the network capable of controlling one controlled device. For example, a wireless phone can consist of a handset and several base stations available in the network. Each base station, being a controlling device, is capable of controlling the handset, which is the controlled device in this example. When the user is making a call, he may move outside the range of the first base station and into the range of the second base station. It would then be advantageous if the second base station could take over control over the wireless phone, so that the user can continue his call. Other wireless devices may be in similar situations when they are moved around. A handheld remote control unit, used to send commands devices in the network, in particular is moved around very frequently and may need a different controlling device to receive the commands for further transmission in every room. Devices connected to the network with a wire may also be moved from one location to another, for example when a user takes a portable TV from the living room to the kitchen. In the present situation, when this device is connected in the second location, a new controlling device needs to be selected which will control the controlled device. The new controlling device must then install an abstract representation (AR) for the controlled device, after which other devices can access the functionality of the controlled device. However, from a user""s perspective, the controlled device has now returned to its initial state, and has forgotten the settings the user made, such as the song currently being played or which options were selected on an amplifier.
In addition, when the controlled device is disconnected, all interactions with other devices are ended. After the controlled device has been connected again on the new location, these devices can again interact with it, but they will have lost their current state of the interaction as well.
It is an object of the invention to provide a communication system according to the preamble, in which control over a controlled device can be transferred to another controlling device in a transparent and automated fashion.
This object is achieved according to the invention in a communication system that is characterized in that the system has migration means for selecting a second controlling device from said plurality based on a predetermined criterion and for generating a migration event, and in that the first controlling device is arranged to transfer control over the controlled device to the second controlling device in response to the migration event. In systems according to standards such as HAVi, devices communicate using messages and events, and it is possible to define new events, such as migration events, not defined in the standard. By receiving a migration event, preferably containing an identifier for the second controlling device, the first controlling device can find out to which device control should be transferred. Since it may be possible that more than one device is capable of receiving the transferred control, the system must select one such capable device first.
In an embodiment the predetermined criterion comprises a level for the quality of a connection between the controlled device and any of the controlling devices from said plurality. When using this criterion, a transfer can be initiated when the second controlling device is found to have a higher quality connection than the first controlling device. An advantage of this embodiment is that the quality of the connection is easy to measure, and techniques to do this are well known, e.g. from mobile phone technology.
In a further embodiment the predetermined criterion comprises a level for the availability of resources on the controlling devices from said plurality. When using this criterion, a transfer can be initiated when the second controlling device is found to have more resources available than the first controlling device, or when the first controlling device is found to have too few resources available to continue controlling the controlled device. An advantage of this embodiment is that it allows for a better distribution of used resources over the available devices. A further advantage is that the first controlling device can now transfer control when it becomes too busy.
In a further embodiment the first controlling device is arranged to transfer control by transferring the AR for the controlled device to the second controlling device. An advantage of this embodiment is that this requires no special functionality in the second controlling device, as uploading of ARs to controlling devices is well known in systems such as HAVi. In this embodiment, the first controlling device simply uploads the AR to the second controlling device.
In a further embodiment the first controlling device is arranged to additionally transfer the current state of the AR to the second controlling device. An advantage of this embodiment is that the settings and selections made by the user will now still be set and selected after the transfer, thereby increasing the transparency of the transfer. This can be achieved by uploading the AR together with data associated with the AR to the second device.
In a further embodiment the second controlling device is arranged to receive the transferred control by creating an interface to the AR which interfaces with the AR on the first controlling device. An advantage of this embodiment is that the state of the AR is not modified, as the AR stays in place on the first controlling device. Other devices interacting with the AR can still do so. The first controlling device now acts as a proxy, exchanging messages with the second controlling device.
In a further embodiment the first controlling device is located in a first cluster comprising devices from said plurality and the second controlling device is located in a second cluster comprising devices from said plurality, said first and second clusters being interconnected via respective gateway devices. An advantage of this embodiment is that the transfer of control is now also possible when the first and second controlling devices are not in the same cluster. The migration event may need to be transferred via the respective gateway devices from the second to the first cluster.
It is a further object of the invention to provide a controlling device according to the preamble, which can transfer control over a controlled device to another controlling device in a transparent and automated fashion.
This object is achieved according to the invention in a controlling device that is characterized in that the controlling device is arranged to transfer control over the controlled device to another controlling device in response to the migration event.
In an embodiment the controlling device is arranged to transfer control by transferring the AR for the controlled device to the other controlling device.
In a further embodiment the controlling device is arranged to additionally transfer the current state of the AR to the other controlling device.
It is a further object of the invention to provide a controlling device according to the preamble, which can receive control over a controlled device transferred from another controlling device in a transparent and automated fashion.
This object is achieved according to the invention in a controlling device that is characterized in that the controlling device is arranged to receive control over the controlled device transferred from the other controlling device by creating an interface to the AR which interfaces with the AR on the other controlling device.
It is a further object of the invention to provide a controlling device according to the preamble, which can initiate the transfer of control over a controlled device to another controlling device in a transparent and automated fashion.
This object is achieved according to the invention in a controlling device that is characterized in that the controlling device has migration means for selecting another controlling device from said plurality based on a predetermined criterion and generating a migration event. The reception of said migration event initiates the transfer of control.
It is a further object of the invention to provide a controlled device whose control can be transferred from one controlling device to another controlling device in a transparent and automated fashion.
This object is achieved according to the invention in a controlled device that is characterized in that the controlled device has migration means for selecting another controlling device from said plurality based on a predetermined criterion and generating a migration event. The controlling device currently controlling the controlled device will then automatically transfer control over the controlled device to the other controlling device, in response to said migration event.